CR702 radio diode BIT order

[bluebrickrick]

Ooops, useless with out the bit order and values per bit if a diode is installed
This for the CR708, still working on the 702
Hope the workings make sense, each diode has a value of 1, 2 or 4, this value counts if there is a diode (1) fitted in that position, sum the values of each block of 3 (Noting the order which seems to be what varies from model to model) note if it = 7 count it as 1 if it = 0 count it as 6. sum of each 3 - 1 digit of the code, there may be alternative combinations and they seem to love repeating digits to be annoying.
Or as someone suggested by PM don't be a NERD, go buy a new one

Sorry, seems to have screwed up my columns but hopefully still understandable......

value diode? equals
D12_ 4_ 1_ 4
D11_ 2_ 0_
D10_ 1_ 1_ 1_ 5

D6_ 4_ 0_
D7_ 2_ 1_ 2
D8_ 1_ 1_ 1_ 3

D2_ 4_ 0_
D3_ 2_ 1_ 2
D4_ 1_ 1_ 1_ 3

D9_ 4_ 0_
D5_ 2_ 1_ 2
D1_ 1_ 0_ __ 2
Code= __5332

[Jungle_Jim]

Hi all

I have just bought a CR-702 which has no codes.

Just a thought - with the diodes - would it be possible to cut one leg on all the diodes, so there was effectively no diodes, and use 6666 as the code? Or do the diodes somehow relate to what's on the eprom? I guess they do - that would be too easy otherwise!

Or Bluebrickrick - have you cracked the code with the diodes? Apologies I'm not able to get how you're establishing that pattern but it seems promising.

Thanks all
John

[cupton9]

Originally Posted by bluebrickrick

'New' radio installed and both radio and cassette working nicely.

I only realised after cleaning the bezel that the one coming out was actually a CR708 so direct comparison with the CR702 may not be possible as it has a different PCB

However in case it helps someone else on the same quest, here are the diodes installed (1) or not (0), its code is 5332

D
1 0
2 0
3 1
4 1
5 1
6 0
7 1
8 1
9 0
10 1
11 0
12 1
Thanks VOC Forum members for another win

Hi, Newbie here so please bear with. Hopefully I'm posting this is the right place! I note from these messages that there is software to decode the CR-702? Any chance I could be sent a copy of the software (or anyone could possibly help!?). The code Volvo dealership gave me from the serial number doesn't work. I don't really know what I'm looking for, but having opened it up slots 1, 2, 5, 9 & 12 on the circuit board are empty. Any help or guidance would be amazing!! Trying to save the old radio. Thanks, Chris

[Piet22]

The code should be 6643 or 6136.




The program itself can be downloaded as a zip-file from my Onedrive: Link. It has been checked on viruses with Bitdefender.

[cupton9]

Originally Posted by Piet22

The code should be 6643 or 6136.




The program itself can be downloaded as a zip-file from my Onedrive: Link. It has been checked on viruses with Bitdefender.

Thank you Piet22... I stupidly have only just seen this message! Ended up sending to a business in Chesterfield to get it decoded, but now at least fully working!

[liammedler]

Thank you for that, just decoded my stereo perfectly with your download

[sjafen]

Hello Piet22. I read in forum that you are able to help me with code for my new bought Volvo CR-702 car stereo? I have diode in 3,4,5,7,11,12. I hope you are able to help me. Thanks, Tor Erik Førland, Norway.

[Piet22]

Link to download the program:
https://1drv.ms/u/s!AiZU1IHSFEZlgdFD...QLGNQ?e=kPzaZV

The program is virus-free according to Bitdefender.

[Volvistas]

Originally Posted by Piet22

It is even more complicated.
The code calculator program I used this morning has two settings: a common variant and a CR705 variant.
I have another code calculator program that does the same but uses two separate programs. One is called CR-905 calculator and the other is called CR-705 calculator.
The results of the common variant (top left) are always the same as the results of the CR905 calculator (top right)
However, the results of the CR705 variant (bottom left) are not always the same as the results of the CR705 calculator (bottom right) So one of the two probably has a programming error.
Unfortunately, with your diode configuration both programs give the same results so that does not help me to find out which of the two programs cannot be trusted. I suspect the bottom right version sometimes displays a 6 when it should be a 1 but I'm not sure.









If you send me a pm with your email address I'll mail you the programs. Bitdefender has declared them all virus-free.

Hello, can you help me to find my radio code?

Serial no.:
VO1850 Y9191157C

Model:
CT-505

Thanks! 🙂

[Forrest]

If you look at post #5 in this thread it shows you in broad terms how to read the code off the eprom in your model of radio. The code calculator only works for radios which use diodes.